Hello,
It looks like I have the same issue using GateIn 3.0 (Tomcat) or GateIn 3.1cr1 (JBoss)
I stepped through the code and when the store() method is called my new preference is removed from the updates but not added to the permanent preferences.
Also there is this sentence "The store method can only be invoked within the scope of a processAction call." in http://portals.apache.org/pluto/portlet-api/apidocs/javax/portlet/PortletPreferences.html#store()
But in practice, it sounds logical that it should work: "... you can make some state changes in the serveResource call: Change the portlet preferences ..." http://www.ibm.com/developerworks/websphere/library/techarticles/0803_hepper/0803_hepper.html#N10186 and it works in Liferay 6.
Did I miss something ? What is the status on this ??
Regards
Bruno